Apparatus and method for a drill mud plant

Abstract

A remediation plant for remediating drilling mud, cuttings, and fluids. The preferred plant includes a reboiler that is adapted to provide heat to the drilling mud, cuttings, and fluid, a mud drum that is operatively connected to the reboiler, a distillation column that is operatively connected to the reboiler, a heat exchanger that is operatively connected to the reboiler, a condenser that is operatively connected to the distillation column, a condenser tank that is operatively connected to the condenser, an oil-water separator that is operatively connected to the condenser tank, and a pump that is operatively connected to the oil-water separator. The preferred remediation plant is adapted to remove synthetic drilling fluid from drilling mud, cuttings, and fluids. A method for remediating drilling mud, cuttings, and fluid.

The invention claimed is: 
     
       1. A method for remediating drilling mud and cuttings that include a solids portion, the method comprising steps of:
 providing a remediation plant comprising:
 a vacuum distillation unit (VDU) that includes a vacuum-assisted distillation column and a condenser; and 
 an oil-water separator; 
 
 reducing a pressure within the distillation column to a reduced pressure that is less than atmospheric pressure; 
 distilling the drilling mud and cuttings, including the solids portion, within the distillation column at the reduced pressure by raising a temperature of the drilling mud and cuttings to a temperature that is less than a cracking temperature of a drilling fluid that includes hydrocarbons having a chain length up to C 24  and that does not include hydrocarbons having a chain length equal to or greater than C 25  in the drilling mud and cuttings such that a liquids portion of the drilling mud and cuttings including hydrocarbons having a chain length up to C 24  and not including hydrocarbons having a chain length equal to or greater than C 25  forms a vapor; 
 separating the vapor from the solids portion of the drilling mud and cuttings; 
 in the condenser, condensing the separated vapor to form a condensed liquid; and 
 using the oil-water separator, segregating the condensed liquid into a recovered drilling fluid that is physically and chemically equivalent to a virgin form of the drilling fluid and a water-containing portion. 
 
     
     
       2. The method of  claim 1  wherein the reduced pressure ranges from approximately 10 mmHg to approximately 30 mmHg. 
     
     
       3. The method of  claim 1  wherein the step of segregating the condensed liquid using the oil-water separator is carried out at atmospheric pressure. 
     
     
       4. The method of  claim 3 , wherein, following the step of reducing a pressure within the distillation column, only the step of segregating is carried out at atmospheric pressure. 
     
     
       5. The method of  claim 1  further comprising a step of limiting a maximum molecular weight of hydrocarbons contained in the vapor using at least one of temperature and pressure in the distillation column. 
     
     
       6. The method of  claim 1  further comprising a step of reinjecting at least a portion of the condensed liquid back into the VDU in order to increase a purity of a resulting hydrocarbon-containing portion. 
     
     
       7. The method of  claim 6  further comprising a step of, prior to segregating condensed vapor using the oil-water separator, gravity separating the condensed vapor in order to separate the hydrocarbon-containing portion from a water-containing portion. 
     
     
       8. The method of  claim 1  wherein the remediation plant further comprises a heating system for heating the drilling mud and cuttings within the VDU having a heat exchanger comprising a recirculating loop and wherein the drilling mud and cuttings are heated to a temperature that is within a recovery range between 65° C. and 185° C. by circulating through the recirculating loop. 
     
     
       9. The method of  claim 8  further comprising a step of, while the drilling mud and cuttings are circulating in the recirculating loop and are heated to be within the recovery range, injecting fresh drilling mud and cuttings into the recirculating loop such that water in the fresh drilling mud and cuttings is immediately flashed into steam and steam strips the drilling mud and cuttings. 
     
     
       10. The method of  claim 1  further comprising a step of cooling a top portion of the distillation column such that a first portion of the vapor that is comprised of heavier hydrocarbon fractions having a first molecular weight condenses and remains in the distillation column, while at the same time a second portion of the vapor that is comprised of light hydrocarbon fractions having a second and lighter molecular weight is separated from the first portion of the vapor and is condensed in the condenser. 
     
     
       11. The method of  claim 1  wherein the step of distilling the drilling mud and cuttings is continuous. 
     
     
       12. The method of  claim 1  further comprising a step of supplying the condensed vapor from the condenser into a condenser tank at the reduced pressure, isolating the condenser tank from the distillation column, and then decanting the condenser tank.